Field of the Invention
This invention relates to gasket sheets which have good sealing properties even at low flange pressures. More particularly, the present invention provides a gasket which can be used to seal fluids. Gaskets of the present invention, placed in a flange and having to seal against fluids, can seal against fluid leaks both going through the gasket sheet internally and across the gasket face.
Gasket sheets are used to seal fluids in engines. A number of solutions have been employed in order to obtain good sealability (sealing ability) in the gaskets.
Beading on the face of the gasket is known. Such beading is a raised area put on the face; this beading, however, does not extend past the edge and further does not extend onto the edge. Such beading is used to enhance sealing.
One gasket material which can be used to give a good seal at high temperatures is described in U.S. Pat. No. 5,240,766. This reference describes a gasket sheet material having fiber, filler, and binder. According to the reference, the filler component provides desirable sealability.
Another reference which describes gasket sheet materials is U.S. Pat. No. 5,536,565. This reference describes a gasket sheet material with fiber and filler. The filler component must include a gel-forming mineral. This filler gives the gasket good sealing properties, especially against polar liquids.
In spite of the wide use of gaskets to obtain a seal against fluids in engines, obtaining a good seal continues to be a problem in gasket sheet materials. Many gaskets do not seal well at low flange pressures. Other gaskets are given particular coatings in order to obtain a gasket sheet which will seal well. Unfortunately, such coatings are then responsible for the gasket having poor compression failure resistance.
The gaskets described herein provide good sealing ability even at low flange pressures. In some embodiments the gasket is not coated or has only a limited amount of a coating given in order to obtain good sealability, thus allowing the gasket to also be compression failure resistant.